A leading figure in Japan's national elections says his country should acquire nuclear weapons if it wants to be taken seriously.

Shintaro Ishihara resigned earlier this month as Tokyo's governor to run in next month's general election as the head of a new right-wing party, which may play a role in choosing who governs the country.

As the only country to have been the target of atomic bombs, Japan has a long-standing ban on acquiring nuclear weapons.

However, speaking to foreign journalists, 80-year-old Mr Ishihara said Japan should at least investigate acquiring nuclear weapons, saying the diplomatic sway of countries without them was weak.

Mr Ishihara has a long track record of inflammatory remarks, blaming foreigners for terrible crimes, and saying last year's massive earthquake and tsunami was divine punishment for Japan's greed.